1. Field of Invention
The present invention refers to an improved kind of oven for cooking food, comprising a door—as generally known as such in the art—for gaining access into and closing the cooking cavity of such oven, this door being provided with at least a clear, see-through window adapted to allow the interior of the cooking cavity of the oven to be watched, i.e. inspected during the cooking process.
2. Desription of Related Art
According to the prior art, these kinds of windows are made up by two or more glass panes of a special type, which are disposed in a parallel arrangement relative to each other and are kept firmly in place relative to each other by means of a common peripheral support frame, which acts as the actual window casing or framework, and which is provided—on a vertical side thereof—with hinges adapted to engage appropriate pins provided on a vertical edge on the outside of the cooking cavity of the oven.
The volume that is comprised, i.e. the gap existing between said two glass panes and enclosed by said peripheral frame forms a sealed intermediate chamber therebetween, the purpose of which lies in thermally insulating the inner cooking cavity of the oven from the outside ambient, so that the temperature of the outer surface of the outer glass pane of the door window—i.e. the surface that is directly accessible by an operator—is not able to reach any such high value as to impair the safety in using the oven. In this connection, it should further be noticed that the internationally applying standards regulating the construction of these ovens require that such outer temperatures shall never be able to exceed definite highest allowable values.
While reference is made throughout the following description to a food cooking oven specifically intended for use in professional kitchens, such as in particular mass-catering foodservice applications, in which the inner temperature in the cooking cavity may reach up to particularly high values, it will nevertheless be appreciated that what is being explained, illustrated and generally set forth in the same specification may be understood as equally applying to—and thus used in—food cooking ovens and similar appliances as typically intended for home, i.e. household use.
During a cooking process, owing to the really considerable temperature differences that come to exist between the outside ambient, which lies generally at ambient temperature, and the temperature prevailing inside the afore-cited sealed chamber formed between the window panes of the oven door, a moisture or condensate film—i.e. a so-called mist—can be most frequently noticed to form on the inner surface of the outer glass pane. Such circumstance is largely known to be disadvantageous in that it practically prevents the food in the cooking cavity, and thus the cooking state and/or degree thereof, from being properly observed by the operator who has to survey the progress of the cooking process from outside. Under the circumstances, therefore, for the state of the food being cooked to be able to be visually inspected as required, the operator should first of all open the oven door. However, opening the oven door as a cooking process is going on is largely known to imply a whole set of other rather serious drawbacks, which, owing to them being largely known in the art, actually, shall not be reminded here.
In an effort to eliminate such condensate film, or mist, forming inside the oven door window, the solution has therefore been largely adopted up to now consisting in allowing or, better, causing a stream of air taken in from outside—and which is therefore relatively much less humid and certainly cooler than the air existing inside the chamber between the glass panes of the door window—to flow through the same chamber.
This solution has in practice been found to be generally most effective in solving the basic problem; however, it can readily be appreciated to be connected with definite counterweighing drawbacks in terms of increased construction costs and complexity, owing to appropriate means and devices having or course to be specially provided for such air stream to be able to be generated, be blown into and through said chamber, and be eventually caused to exit it and be exhausted outside.
In view of doing away with such drawbacks, the practice is known—e.g. from the disclosure in DE 299 22 756 U1—of providing a food cooking oven with a door equipped with a glass pane on which there are arranged heating means, particularly in the form of electric wires.
The basic purpose of such electric wires consists in heating up the region in which the glass pane lies, so as to improve the temperature of the zone of the oven cooking cavity lying contiguous to said pane, thereby also obtaining the additional, auxiliary result of improving the visibility of the cooking cavity interior from outside, since said heating means are effective in causing the moisture film that may condense on the inner surface of said pane to evaporate.
This solution, however, turns out as being rather tricky and delicate owing basically to the fact that there certainly is a great number of electric wires to be connected and that, therefore, the periodical cleaning, which the inner surface of the glass pane has necessarily to undergo, may affect the efficiency thereof. Furthermore, this solution is certainly such as to affect the overall outlook, i.e. aesthetics of the product. Finally, it has also to be noticed that, under extreme conditions of temperature and moisture, the desired removal of the condensate layer from the glass pane is hardly obtainable unless the electric wires are arranged very close to each other in a thick pattern, i.e. a condition that would further deteriorate both the internal visibility and the overall outlook of the oven.
The just described solution has been the subject of a prior disclosure in the publication DE-GM 8716665.8, actually. Although the claimed purpose of such utility model lies solely in eliminating the condensate layer, or film, from the inner surface of a glass pane inserted in the door closing the cooking cavity of an oven, the kind of solution taught in said publication is however the same, so that the same considerations as set forth above equally apply in this case, no need arising therefore for them to be indicated and explained again.